1. Field of the Invention
The present invention relates to a method of determining a maximum adhesion coefficient of a tire running on ground.
2. Description of the Related Art
The maximum adhesion coefficient of a tire varies as a function of the running conditions of the tire, in particular as a function of type of road on which the tire is running, or as a function of temperature.
It is most advantageous to know the maximum adhesion coefficient of a running tire in real time in order to determine whether or not the tire is close to losing its grip on the ground.
This information relating to the adhesion of the tire can be transmitted to the driver of the vehicle fitted with the tire so as to enable driving to be adapted accordingly, or to an electronic device for controlling the road holding of the vehicle.
In the state of the art, and in particular in WO 03/066400, it has been shown that it is possible to determine the adhesion coefficient by measuring the three components of the forces applied to the tire, the self-alignment torque, the pressure of the tire, and the camber of the tire.
It is possible to determine the adhesion coefficient by using a transfer function that receives as inputs the various measured parameters and that delivers as an output an estimate of the adhesion of the tire. The characteristics of the transfer function can be determined, for example, by using a conventional method of training the weights of a neural network.
The training period nevertheless requires tests to be performed during which the tire is subjected to different conditions of use. In particular, it is necessary also to take account of parameters that vary slowly such as the wear or the aging of the tire in order to optimize determining the characteristics of the transfer function.
Because of the large number of parameters to be taken into account, the transfer function used in the state of the art is a function that is very complex and expensive to use, and that requires training that is lengthy. In order to ensure that the characteristics of the transfer function take account of all of the parameters, it is necessary to perform tests in which each of the parameters is varied independently of the others.
There is therefore a need to provide a tape that overcomes one or more problems in the prior art.